The present invention relates to a printer suitable, for example, for use with electronic cash registers used in point-of-sale (POS) systems and relates, more particularly, to a printer comprising a restraining module for its cutter having a moving blade and a fixed blade so as to maintain an appropriate gap between the moving blade and the fixed blade when the printer moving is approaching the closed position thereby allowing smooth engagement of the fixed and moving blades.
Printers used in point-of-sale (POS) systems generally print to rolled paper as the recording medium using a thermal head or other type of print head, and comprise a cutter to cut the printed paper to obtain a sales receipt that can be handed to the customer.
Typical of the various cutters employed in such printers are cutters that cut the paper by pushing a cutting blade perpendicularly against the paper as described in JP-A-238970/1994, and cutters that cut the recording paper using a fixed blade and a moving blade as described in JP-U-123482/1979. A scissors-type cutter that cuts the recording paper by moving a moving blade across the paper while cutting the recording paper from one edge to the other is also known as described in JP-U-10953/1990, and U.S. Pat. No. 5,833,380.
In such conventional printers, while engaging the moving blade to the fixed blade, the moving blade is constantly pressed unto the fixed blade during the entire engagement process. Such an engagement manner thus easily result in damages and scratches of either the moving blade or the fixed blade such that after multiple engagement, cutting edges of the moving blade and the fixed blade may be dull and thus require replacement or re-sharpening.
It is thus needed to design a restraining module for a cutter of a printer, that restrains the moving blade from contacting the fixed blade prior to complete engagement of the two blades so as to allow smooth engagement, but provides sufficient force subjecting the two blades to work closely to one another so as to provide neat cutting results.
The object of the present invention is to provide a restraining module for a cutter of a printer overcoming the problems of the prior art as described above and being able to prevent from damaging the fixed or moving blade during engagement of the two.
It is a further object of this invention to provide a restraining module for a cutter of a printer that implements obstruction between a moving chassis and a fixed chassis of the printer prior to the printer reaching its closed position so as to prevent the moving blade from contacting the fixed blade prior to their full engagement.
Another object of the present invention is to provide a printer including such a restraining module for a cutter.
To achieve the above objects, disclosed is a printer having a restraining module for a cutter thereof, the printer including: a fixed chassis; a moving chassis being engageable with the fixed chassis between an open position and a closed position; the cutter including a fixed blade and a moving blade being pivotally mounted to the moving chassis; a paper drive roll; a thermal head; and driving means driving the paper drive roll to subject paper rolling between the thermal head and the paper drive roll and then between the fixed blade and moving blade; wherein the thermal head is in a path of the paper drive roll and wherein the moving blade presses and urges the fixed blade towards the fixed chassis when the moving chassis is at the closed position, the restraining module comprising: a first angle control means mounted at the fixed chassis normally forcing the fixed blade to incline away from the fixed chassis; and a second angle control means mounted at the fixed chassis and activated by the moving chassis to force the fixed blade to incline away from the moving chassis when the moving chassis is engaging the fixed chassis.
Further objects and advantages of the present invention will become more fully understood from the detailed description of the preferred embodiments given below in conjunction with the accompanying drawings, wherein: